Risk adjusted mortality rates have become the ‘holy grail’ for policy wonks, media and government agencies to report on the ‘best’ hospitals and doctors. Alas! Peter Pronovost a Hopkins Professor and a researcher from the University of Birmingham in England report in the British Medical Journal that risk-adjusted mortality rates are a “poor diagnostic test” to measure hospital quality and the statistic should be only one of many factors considered when comparing hospital performance. Their study makes two main points: 1. Risk-adjusted mortality rates do a poor job of separating preventable deaths from deaths due to other causes because risk adjustment accounts only for factors that can be “identified and measured accurately.” 2. Risk adjustment fluctuates between regions and causes, exaggerating discrepancies across hospitals. They also point out that about 5% of in-hospital deaths have been deemed ‘preventable.’ The authors suggest instead non-mortality stats such as hospital acquired infection rates, outcomes of high risk procedures and clinical processes such as anti-coagulants prior to hip surgery as better markers of quality. Comment: This makes sense that even the best risk adjusted numbers are sometimes flawed and real co-morbidities are not measured accurately.